Leaking Moen Kitchen Faucet

My friend and I are trying to fix my leaking Moen kitchen faucet (single handle). It looks like it is pretty old. Probably from the 70's or 80's but when I did an internet search of the model number MT800 I came up with a very new modern looking faucet. Do they reuse old model numbers?

Also we could not get the diverter out/off. Any suggestions? We replaced the o-rings and put it back together and it's leaking worse than ever. I have to keep a towel wrapped around it when I turn it on. It does not drip from the spout. Just leaks alot around the base/handle area.

After replacing the cartridge, taking it out again, putting it back in, going back to the hardware store (rinse and repeat) for a whole day we finally decided to buy a new faucet next week. The thing was still leaking. At one of our trips to the hardware store, the guy had suggested we lube everything up really well with plumbers grease when we told him it was really hard getting the new cartridge in. So we tried that. Didn't help. Took it out again fiddled around. Didn't help. Called it a night. Ordered a pizza. Put the thing back together just so I could do dishes later that week albeit with a towel wrapped around the thing again and lo and behold....... the leak is gone. And this thing had been running like a small creek. What gives?

My question now is....We lubed everything up pretty good with that grease. Is that now getting into my drinking and cooking water? I drink a lot of water and that idea bothers me a lot. On the back of the tube of grease it says do not take internally. Now I realize they probably mean - don't eat it but I wonder if any of you know is it bad for it to leach into your water. If so I'm thinking after all this work now maybe I should just go get a new faucet to resolve this.

I was guessing from the location of the pink towel that it was leaking around the base of the spout??? If that was the case, the spout o-rings should have fixed it . A bad cartridge might have been stiff to turn on, and may have been dripping out the spout, and possily leaking at the base of the handle area.

A little grease is a good thing. The new cartridge should have come with sufficient grease already on it. Gooping up the spout o-rings may have provide temporary relief, but if they were leaking, they may leak again soon. Faucet grease is used all the time, but strictly speaking is not NSF certified. You could have used NSF-grade silicone grease as well.

Grease is not water soluble, so you will not get a lot of it in the water. You could do a long flush to try to remove any great excess whicy is present.

It was leaking out the top of the cartridge (the hole near the top of the brass part of the cartridge). The towel catches the water after it flows down. We replaced the seals and the cartridge. We actually had to replace the seal at the bottom of the new cartridge as well because the cartridge went in so hard that the seal broke. Even after liberal greasing the cartridge went in really hard.

If it does start leaking again I'm ready for a new faucet.

Thanks for the information on the grease. I feel better knowing it's normally there anyway.